Page 81 - Root Cause Failure Analysis

PROCESS PERFORMANCE

While the principles of RCFA can be used for almost any problem, the most prevalent
application in an integrated plant is to resolve process-performance problems. These
events normally do not result in catastrophic failure of critical plant systems or per-
sonnel injury, but they have a measurable, negative impact on the financial perfor-
mance of the plant.

Resolution of deviations in process performance, such as operations problems (e.g.,
reduced product quality or capacity) or economics problems (e.g., high costs), often is
more difficult than investigation of equipment failures or accidents.

Events like equipment failure or accidents have an absolute time of Occurrence that
facilitates an investigation. Once the event's time frame is established, the investigation
can isolate all the variables and possible causes that may have contributed to the prob-
lem. Most process problems also have a unique timing associated with the deviation, but
it is much harder to isolate. As a result, the investigation often is more difficult.

The recommended methodology for this type of RCFA is a cause-and-effect analysis.
The technique of diagramming the potential causes of a specific event, such as prod-
uct quality, loss of production capacity, or increase in operating costs, provides the
structure and order needed to quickly and methodically resolve problems.
The cause-and-effect approach forces the investigator to identify each factor or vari-
able that can contribute to a specific event. Once identified and graphically plotted in
a fishbone diagram, the investigator or investigating team can quickly and easily eval-
uate each of the potential variables.

After the initial evaluation process, some of the initial factors will be eliminated. The
investigating team should perform a cause-and-effect analysis on each of the remain-
ing factors. In this evaluation, the factor being investigated becomes the eflect in the

72